Set up
A military transport is dilivering 4 of the worst phycos to get created in the galactic wars. There collective acts of extream violence and brutality has earned them a respit from the war and a long stay at the pluto penal colony.
As they were on route to there prison for life they are given new orders, to check out the signal loss with the mars colony. Pardons all round for solving the mars problem.
So wat have we got?
2 crap usless gaurds, 4 hardcore sci fi solgers, the badest pof the bad, a scary mars base full of zombies, monsters mutants, ready for chainsawing, shotgun'n and genral killing as the Doomed guy trys to close the doors to hell that is slowly sucking our reality in.
How is it like the game?
Well you start with 4 player co-op, then as there genral phyconess and the situations get wierd they turn on each other, 4 player deathmatch. The Doomed guy meets up with some chick still alive (always need a servivour to point the heros in the correct direction

= 4 player Team Deathmatch. After killing the other troops, they doomed guy gets seperated, single player mode, guy acidently turns courner running from monsters and blows cheast out of friend chick.. his mind snaps and wears her as a backpack, doing ash like chatting to the corpse, with slowly fgall apart over rest of film., uses corpse at end to prop open a lowering door = 2 player co-op
The doomed guy meet the cyber deamon..... kills the fucker only to be sucked into hell as portal closes.
What we got?
Phyco hardcore freak in hell killing monsters for a sequal.